Optimally if you need to cut regularly (e.g. "career competitor"), they recommend you stay w/in 15 lbs of your goal weight & 5% bf so you don't go thru those extreme swings. The male pros go crazy off season-- ever see King Kamali off seaons?? Ronnie?? LEE PRIEST?? Nutso. Those guys will PAY for those weight swings in the future. But as Daisy said, my experience, if you go thru severe weight swings that you don't anticipate over short periods of time, these screw w/ your brain & your attitude (thus your well-being) and also your body may just decide it isn't go to play that game any more & just shut you down. The harder you try to achieve where you think you should be mentally but aren't geting those results, the more you start over training and worrying and then you are double-fucking yourself.